Wiper arm

ABSTRACT

The invention is based on a wiper arm ( 10 ) that is comprised of a mounting part ( 12 ) and an articulating part ( 14 ), which is pivotably connected to a first region ( 16 ) of the mounting part ( 12 ) by means of a hinge joint ( 22 ) and has a wiper rod ( 24 ), to which a wiper blade is pivotably connected, wherein the mounting part ( 12 ) is securely affixed with a second region ( 18 ) to a drive shaft ( 20 ) and braced in relation to the articulating part ( 14 ) by means of a tension spring ( 28 ). The invention proposes that the mounting part ( 12 ) have a device ( 34, 36, 42 ), which permits the first region ( 16 ) of the mounting part ( 12 ) oriented toward the articulating part ( 14 ) to collapse toward a vehicle windshield in a defined manner.

PRIOR ART

[0001] The invention relates to a wiper arm according to the preamble toclaim 1.

[0002] Known windshield wipers have a wiper arm that is comprised of amounting part and an articulating part pivotably connected to it, whichhas a wiper rod. The wiper rod has a wiper blade pivotably connected toit, which is comprised of a wiper strip and a support bracket systemwith a primary center bracket and pivotably connected secondaryintermediate brackets and claw brackets.

[0003] The articulating part has a spring chamber for a tension springat its end-oriented toward the mounting part. The spring chamber is opentoward the vehicle windshield and has a slot-shaped extension, which isoriented toward the wiper rod and has a first anchor point on which asecuring bracket of the tension spring is suspended. The other end ofthe tension spring is provided with a C-shaped bracket, which issuspended on a suspension device of the, mounting part; this suspensiondevice serves as the second anchor point. The articulating part is alsosupported by means of a hub on a bolt-shaped hinge pin, which isdisposed in a first region of the mounting part oriented toward thearticulating part. The joint thus produced, also called a hinge joint,and the suspension device of the tension spring, are disposed inrelation to each other so that the tension spring pulls the articulatingpart and the wiper rod with the wiper blade toward a vehicle windshield.

[0004] The articulating part of the windshield wiper is folded away fromthe vehicle windshield for cleaning or installation of the wiper blade.To this end, the articulating part is pivoted around the hinge pin ofthe hinge joint, during which the tension spring assumes a position inwhich it pulls the articulating part against a stop, which is supportedon the mounting part and limits the pivoting motion.

[0005] A second region of the mounting part is mounted on the free endof a drive shaft, which is supported in a wiper bearing and driven by awiper motor by means of a crank and a rod assembly. The wiper motor isheld in place by a mounting plate, which is mounted on the vehicle bodyand which contains wiper bearings. Frequently, the wiper bearingsthemselves serve as anchor points by passing through openings in thevehicle body and being screwed into the vehicle body with theinterposition of vibration-damping rubber elastic elements.

[0006] The end of the drive shaft protruding from the vehicle bodyrepresents a significant danger source for injuries during accidentswith pedestrians. With regard to accidents with pedestrians, EuropeanCommission outlines for crash regulations (EC HIII/5021/96 EN) definemaximum acceleration values, so called head injury criteria, in thevicinity of the vehicle hood and the wiper system. These criteria cannotbe met with conventional wiper systems, even if the vehicle hoodoverlaps the drive shaft, because in this case, too, there is noassurance that the vehicle hood and the drive shaft are far enoughapart, particularly with tight hood clearances.

[0007] One possible solution for this is to shift the end of the driveshaft further into the engine compartment. Vehicle manufacturers requirea minimum distance of 65-85 mm between vehicle hood and the end of thedrive shaft. This also increases the distance from this drive shaft endto the articulating part, requiring a longer mounting part. Besides, atleast during wiping, the mounting part still protrudes into the region apedestrian would strike during impact.

[0008] A wiper system with a moveable drive shaft is disclosed in DE 19803 344 A1. According to this reference, the protruding end of the driveshaft is shifted into the vehicle body when an axial force of apredetermined magnitude acts on the end of the drive shaft from theoutside. In order to cushion the impact, means are provided between aninwardly oriented stop of the drive shaft and a part permanentlyconnected to the vehicle body or between such a part and the vehiclebody; these means plastically and/or elastically deform when acted on inthe axial direction by a critical axial force, causing the end of thedrive shaft to move into the engine compartment in a defined manner.These means can be comprised of a plastically deformable sheet metalsleeve, which suitably has a region that is corrugated in the axialdirection of the axis, or can be comprised of thin-walled, disk-shapedelements, which, depending on the displacement distance, can be disposedoperatively in series. These elements can have such a small amount ofplay in relation to the drive shaft or to other adjacent components thatwhen they deform, they come into contact with these components andthrough friction, increase the cushioning action. Finally, the means canbe disposed so that they are compressed or stretched apart whensubjected to the critical axial force. The drive shaft can also beaxially secured to the bearing housing of the wiper bearing by means ofform-fitting elements with a predetermined breaking point, which breakor bend into available space when subjected to a critical axial force.Predetermined breaking points of this kind can be created by means ofnotches, bores, or shearing pins. Aside from the fact that someembodiments of this principle are very complex structurally, theprinciple is also only effective if the impact occurs in the vicinity ofthe end of the drive shaft.

ADVANTAGES OF THE INVENTION

[0009] According to the invention, the mounting part of a wiper drivehas a device, which allows a first region of the mounting part orientedtoward the articulating part to collapse toward the vehicle windshieldin a defined manner. In the event of an impact, e.g. by the head of apedestrian, the wiper arm immediately yields in the vicinity of themounting part and the articulating part. In this case, the pedestrianwho has been struck does not hit a fixed obstacle, which reduces therisk of injury.

[0010] In one embodiment of the invention, a predetermined breakingpoint of the mounting part constitutes the collapsing device of thewiper arm. This predetermined breaking point is suitably designed as anotch and/or perforation in the side walls of the mounting part and isdisposed at the end oriented toward the drive shaft. One or more notchesand/or perforations weaken the cross section of the mounting part in thedirection of the impact so that, during impact on the wiper arm with acorrespondingly powerful force, the mounting part is designed to breakat this point and the wiper arm is pushed against the vehiclewindshield. Following an accident the wiper arm must be replaced anyway.It is advantageous that this embodiment can be produced with littlestructural expense and requires no additional parts. However, it canalso be applied to other known measures since it is also effective whenthe impact occurs at a distance from the drive shaft and a movement ofthe drive shaft is hindered by tilting moments.

[0011] In one additional variant, the collapsing device is designed as ajoint that connects the second region of the mounting part, which ispermanently connected to the drive shaft and is embodied as a separatecomponent, to a first region, which is also embodied as a separatecomponent. The pivoting motion of the joint is limited in the foldingdirection by a stop. This stop supports the contact force of the wiperarm, which is exerted by a tension spring against the vehicle windshieldand prevents the mounting part from yielding when the wiper folds down.During an impact against the first part of the mounting part indirection toward the vehicle windshield, the first part of the mountingpart yields by tilting around the axis of the joint. To compensate forthe weight of the joint and the wiper parts connected to it when thewiper arm is in a folded position, a spring in the form of a tensionspring is suitably provided, whose line of action extends between thehinge pin and the stop and acts on the two components of the mountingpart.

[0012] In order to embody a transport position and folded position in amore stable fashion, it is advantageous to embody the joint as a latchjoint, in which the initial tension of the spring increases startingfrom a latched position, which corresponds to the operating andtransport position, when the first part is pivoted in relation to thesecond part. This can be accomplished by disposing the anchor point ofthe spring on the second part so that it is offset toward the driveshaft in relation to the hinge pin. In addition, latch surfaces or latchcams can be provided, which are accordingly embodied on either end inrelation to the line of action of the spring in the latched position.

[0013] In one variant, the joint has a hub formed onto a part of themounting part, with a bearing bore, which is embodied as an oblong holeextending in longitudinal direction of the mounting part and is engagedby a hinge pin, which is formed onto the second part of the mountingpart. The oblong hole can be open toward the mounting part to allow foreasier installation. During operation, the two parts support each otherby means of the hinge pin and the stop and are held in this position bythe spring. The initial tension of the spring assures that thepreassembled components of the mounting part do not fall apart duringtransport. If a critical impact force is applied to the wiper arm, thenthe spring force is overcome and the first part of the mounting partcollapses toward the vehicle windshield. The collapsed region of themounting part also causes the hinge joint to fold back slightly from theoperating position. This variant has the advantage that the operatingposition of the wiper arm can be very easily restored by the two jointsbeing folded back into their starting position or by virtue of the factthat they fold back into it automatically. A prerequisite for this isthat the parts of the wiper arm as a whole have not been damaged by theimpact.

[0014] Since the latch joint and the hinge joint have a similar functionand are braced by means of a tension spring, according to one embodimentof the invention, only one shared tension spring is provided for bothjoints, which is secured by means of a cable between a first anchorpoint on the articulating part and a second anchor point on the firstpart of the mounting part. The tension spring can be associated with themounting part or the articulating part. In addition, this embodiment canbe produced without the C-shaped bracket of the hinge joint so that lessspace is required between the wiper arm and the vehicle windshield.

[0015] Basically, all variants of the invention provide protection frominjury in the entire range of motion and in the parked position of thewiper. In addition, the basic, proven design of the wiper arm can remainunchanged. The same is true of the manufacturing process for producingthe wiper arm. The modifications according to the invention to theindividual parts of the wiper arm require only a small amount ofadditional effort, e.g. the adaptation of the injection molds or bendingtools.

DRAWING

[0016] Additional advantages ensue from the following description of thedrawings. Exemplary embodiments of the invention are shown in thedrawings. The drawings, the description, and the claims contain numerousfeatures in combination. One skilled in the art will naturally alsoconsider the features individually and unite them in other meaningfulcombinations. shows a longitudinal section through a wiper arm in theoperating position, shows a variant of FIG. 1, shows an enlargement of adetail III of FIG. 2, without a spring, shows a variant of FIG. 3, witha spring, shows another variant of FIG. 3, with a spring, shows a topview according to an arrow VI in FIG. 5, shows a longitudinal sectionthrough a wiper arm in a buckled position, show variants of FIG. 1,shows a longitudinal section through a wiper arm in the position forreplacing a wiper blade.

DESCRIPTION OF THE EMBODIMENTS

[0017] A wiper arm 10 is basically comprised of a mounting part 12 andan articulating part 14 with a wiper rod 24 (FIG. 1). A wiper blade, notshown in detail, is connected pivotably to the free end of the wiper rod24. The articulating part 14 is connected to the mounting part 12 bymeans of a hinge joint 22. In the operating position shown, the twoparts are braced in relation to each other by means of a tension spring28. One end of the tension spring 28 is suspended in an eye 26 on thearticulating part 14 and at the other end, is suspended on a pin 32 onmounting part 12 by means of a C-shaped bracket 30.

[0018] The mounting part 12 of the wiper arm 10 is securely affixed tothe free end of a drive shaft 20. Close to the drive shaft 20, themounting part 12 has a notch 34 and a perforation 36 in the side wallsof its U-shaped profile. The notch and perforation weaken the crosssection so that, in the event of an accident in which a person isstruck, the cross section functions as a predetermined breaking pointand the mounting part 12 yields easily and/or breaks at this point inthe direction of the impact force 54. In this connection, the size andnumber of the notches 34 and perforations 36 are selected so that themounting part 12 does not break under normal conditions, even when understress from the weight of snow. The predetermined breaking point markedby the notch 34 and the perforation 36 divides the mounting part 12 intoa first region 16, which is oriented toward the articulating part 14 andwhich collapses on impact, and a second region 18, which is mounted tothe drive shaft 20.

[0019] In one embodiment of the invention, the device for the definedcollapsing of the mounting part 12 is constituted by a joint 42 (FIG.2). This joint connects the first collapsing region 16 of the mountingpart 12, which is embodied as a separate component, to the second region18, which is securely affixed to the drive shaft 20 and which is alsoembodied as a separate component. A stop 56 limits the pivoting motionof the joint 42 in the folding direction, but allows it to freely pivottoward the vehicle windshield, during which the end of the first part 16of the mounting part 12, which comprises the stop 56, follows anarc-shaped contour 64 with a radius 66 around the hinge pin 48. In theoperating position of the wiper arm 10, the force of the tension spring28 presses the first part 16 with the stop 56 against the second part 18and thereby converts the recoil force into the force of the wiper arm 10acting on the drive shaft 20. In order to compensate for the weight ofthe articulating part 14 and the parts of the windshield wiper connectedto it in the folded position (FIG. 10) and in order to keep the mountingpart 12 extended in this position, a spring 46 is suitably provided, oneend of which is suspended on a pin 38 of the first part 16 and the otherend of which is suspended on a pin 40 of the second part 18 (FIG. 2).The line of action of the spring 46, which is embodied as a tensionspring, extends between the stop 56 and the hinge pin 48 so that astable balance is achieved.

[0020] The stability of the position can be improved by embodying thejoint 42 as a latch joint whereby the initial tension of spring 46increases significantly in the pivoting direction on both sides of thelatched position, as the distance between the pins 38, 40 increases.This can be achieved by disposing the pin 40 on the second partaccordingly in relation to the hinge pin 48, e.g. by offsetting ittoward the drive shaft 20. In another possible embodiment, the parts 16,18 are supported against each other by means of the latch surfaces 50,52 or latch cams, which shift the parts 16, 18 in relation to each otherduring the pivoting motion, during which the hinge pin 48 can move in ahub, which is embodied as a cross sectionally oblong hole (FIG. 4). Theoblong hole 44, which extends in longitudinal direction of the mountingpart 12, can be open toward the articulating part 14 in order tofacilitate installation (FIG. 5). The latch surfaces 50, 52 can beembodied at any suitable position between the first and second parts 16,18, e.g. in the end region of the side walls of the cross sectionallyU-shaped profile of the first part 16 (FIGS. 5 and 6).

[0021] During an impact, an impact force 54 acts on the mounting part12, causing the first part 16 of the mounting part 12 to collapse. Inthe course of this, the hinge pin 48 functions as the rotation axis andthe first part 16 slides along the latch surfaces 50, 52, whereby theinitial tension of spring 46 is initially increased. The wiper arm 10finally comes to rest in the position shown in FIG. 7. The impact force54 also causes the articulating part 14 to fold out from the extendedoperating position. A corresponding dimensioning of the tension spring28 assures that the articulating part 14 does not completely fold upwardinto the folded position (FIG. 10).

[0022] After an impact, both joints 22, 42 can be reset. In the courseof this, the end of the U-shaped profile of the first part 16 of themounting part 12 oriented toward the drive shaft 20 constitutes a stop56. The stop 56 prevents the first part 16 from collapsing, on the onehand due to the contact force of the windshield wiper and on the otherhand, when the articulating part 14 folds outward.

[0023] In another embodiment of the invention, the hinge joint 22 andthe latch joint 42 are provided with a common tension spring 28 or 46that is mounted by means of a cable between the eye 26, which functionsas a first anchor point on the articulating part 14, and the pin 40,which functions as a second anchor point on the second part 18, (FIG. 8and FIG. 9). The cable 58 is guided between two guide elements 60 on themounting part 12 in the vicinity of the hinge joint 22.

[0024]FIG. 10 shows the articulating part 14 folded upward almostperpendicular so that a wiper blade, not shown in this drawing, which ispivotably connected to the wiper rod 24, can be replaced. In thisposition, an elastic stop 62, e.g. a rubber bumper, which is disposed inthe vicinity of the hinge joint 22 at the end of the articulating part14, suitably prevents the first part 16 of the mounting part 12 frominadvertently striking against the vehicle windshield.

1. A wiper arm (10) that is comprised of a mounting part (12) and anarticulating part (14), which is pivotably connected to a first region(16) of the mounting part (12) by means of a hinge joint (22) and has awiper rod (24), to which a wiper blade is pivotably connected, whereinthe mounting part (12) is securely affixed with a second region (18) toa drive shaft (20) and braced in relation to the articulating part (14)by means of a tension spring (28), characterized in that the mountingpart (12) has a device (34, 36, 42), which permits the first region (16)of the mounting part (12) oriented toward the articulating part (14) tocollapse toward a vehicle windshield in a defined manner.
 2. The wiperarm (10) according to claim 1, characterized in that the device is apredetermined breaking point (34, 36) of the mounting part (12).
 3. Thewiper arm (10) according to claim 2, characterized in that thepredetermined breaking point is comprised by means of a notch (34)and/or perforations (36) in the side walls of the mounting part (12). 4.The wiper arm (10) according to claim 1, characterized in that the firstand second region (16, 18) are separate components, which are connectedby the device, which is embodied as a joint (42) whose pivoting motionin the folding direction is limited by a stop (56). (FIG. 2).
 5. Thewiper arm (10) according to claim 4, characterized in that a spring (46)presses the first region (16) against the stop (56) in an operatingposition and is designed so that it supports the weight of the wiper arm(10) in the folded position of the wiper arm (10) (FIG. 10).
 6. Thewiper arm (10) according to claim 4, characterized in that the joint(42) has a hub with a bearing bore, which is embodied in longitudinaldirection of the mounting part (12) as a cross sectionally oblong hole(44) and which engages on a hinge pin (48), wherein the parts (16, 18)of the mounting part (12) support each other in the operating positionby means of the latch surfaces (50, 52) and/or on the hinge pin (48) andthe stop (56) (FIG. 4, FIG. 5).
 7. The wiper arm (10) according to claim6, characterized in that the oblong hole (44) is open toward thearticulating part (14) (FIG. 5).
 8. The wiper arm (10) according to oneof the claims 4 to 7, characterized in that the spring (46) is a tensionspring.
 9. The wiper arm (10) according to claim 8, characterized inthat the hinge joint (22) and the joint (42) are provided with a sharedspring (28, 46), which is mounted by means of a cable (58) between afirst anchor point (26) on the articulating part (14) and a secondanchor point (40) on the second part (18) of the mounting part (12),wherein the cable (58) is guided between two guide elements (60), whichextend lateral to the longitudinal direction, on the mounting part (12)in the vicinity of the hinge joint (22).
 10. The wiper arm (10)according to one of the claims 4 to 9, characterized in that the end ofthe articulating part (14), which is oriented toward the mounting part(12), has an elastic stop (62), which points toward the vehiclewindshield in a folded position (FIG. 10).